Sines seasonal overview
Best Surf Season (October - March)
Sines is primed for the big stuff when the North Atlantic engine shifts into high gear. From October through March, average open-ocean swell heights run from 5.9ft (1.8m) in October up to 7.9ft (2.4m) in January, while average periods hold solidly in the 12-13 second range. The dominant deep-water direction is actually NW/WNW, but because the beach faces south, the standout days arrive when low-pressure systems tracking across the Atlantic push more S/SW and WSW groundswell toward the Portuguese coast. With offshore N/NNE/NE and NNW winds blowing roughly 50 percent of the time, there are plenty of windows with clean, lined-up surf. When the NAO index turns negative and storms are forced south into Iberia, Sines can fire at pumping, heavy winter standards.
Fair Surf Season (April, May and September)
The shoulder months offer a more relaxed version of Sines. Average swell heights dip to 4.6-5.9ft (1.4-1.8m) and average periods settle in the 10-11 second range. There is still enough west and northwest energy to keep the points and sandbars moving, but the angle is not as consistently favorable and the surf will be smaller. Offshore winds are common, especially in the mornings before the afternoon sea breeze kicks up, so quality can still be high when an S/SW swell arrives. These months are ideal for those wanting a less intimidating, more user-friendly Sines.
Low Surf Season (June - August)
Summertime is the Atlantic lull. The Azores High controls the weather, storm tracks retreat north, and average swell heights bottom out around 4.3ft (1.3m) with average periods of only 8.6-9.3 seconds. The all-powerful NW windswell dominates the ocean, and the south-facing beach is left smaller and more inconsistent. On the flip side, wind conditions are often clean, with offshore N/NNE/NE and NNW flow 55-61 percent of the time. You will not find the pumping groundswells of winter, but small, fun-sized 2-4ft (0.6-1.2m) waves can still be found on a groveler when the swell angle and tide align.